Tool for effecting telescoping engagement between cooperating parts of an electrical connection



Dec. 18, 1956 v G. c. SITZ 2,774,133

TQOL FOR EE EcTINc; TELESCOPING ENGAGEMENT BETWEEN COOPERATING PARTS OF AN ELECTRICAL CONNECTION Filed Feb. 8. 1954 INVENTOR.

ATTORNE United States Patent TOOL FOR EFFECTING TELESCOPING ENGAGE- IWENT BETWEEN COOPERATING PARTS OF AN ELECTRICAL CONNECTION Gilbert C. Sitz, -Harrisburg, Pa., assigor to Aircraft- Marine Products, Inc., Harrisburg, Pa.

Application February 8, 1954, Serial No. 408,632

3 Claims. (Cl. 29-254) The present invention relates to an improvement in tools for eifecting telescoping engagement between cooperating parts of an electrical connection.

One known type of connector includes a tapered plug terminal, or the like, adapted to frictionally engage a receptacle contact member, usually with one or the other of said members in fixed position. This type of connection is advantageous, particularly where many lead wires are to be attached in a small area. However, there remains a risk that operators may make such connections .with a receptacle contact member quickly and securely in a simple operation even where the available working space is limited and the parts are not otherwise readily accessible.

It is also an object of the invention to provide an attaching tool aifording substantially uniform optimum frictional connections for any given type or sizeof-terminal, in part by automatic control of the maximum locating force applied to the part by a given type of tool, and in part by predetermining the energy applied to drive home the terminal afterlocating it by the controlled force.

A further object of the invention has been .to provide a terminal-applying tool which may also be employed for disconnecting a terminal from its receptacle in which it is telescopically engaged. In complex wiringsystems, terminals often have to be so close together that access to individual connections for repair or replacement is difiicult. Moreover, with taper pin connections engagement between the terminal and receptacle may be so secure that they cannot be separated intact by a direct pull. It is an object of this invention to provide a tool by which the connection can be loosened by twisting the removable'part in relation to the fixed part and exerting a pull directly on the removable part, i. e., not through the wire to which it is attached.

In employing a tool according to the present invention to interengage connector parts, one of said connector parts is fitted into the tool and thetool pressed axially to give initial telescoping engagement;andadvantageously --the parts are driven into final frictional engagement, with high radial pressure, by an impact of predetermined magnitude. During the initial inserting operation the tool advantageously cushions the applied pressure and applies .a driving force having the requisite direction and magnitude to bring the connector parts into mating; relation; and advantageously when apredetermined force ,for initial insertion has been reached, the .tool automatically ice applies the predetermined energy to drive the parts into final contact relation.

A convenient form of hand tool according to the present invention includes a handle and a shank (somewhat like an ordinary screw driver) the end of the shank being formed to receive and engage a terminal connector for axial push and to accommodate a wire extending from the back end of the terminal. For more precise insertion, my invention provides a tool comprising a spring-pressed plunger and a hammer mounted for longitudinal movement in a holder, said plunger having a terminal-engaging socket at its outer end and a longitudinally extending channel which opens into said socket for accommodating a wire attached to the terminal, and means for engaging a spring through which it engages with said holder and is pressed by said holder into initial engagement with the terminal, a hammer actuating spring is compressed or loaded to a predetermined extent by initial inward movement of the plunger and the hammer is then released to deliver a driving blow through said plunger to the part initially engaged therewith.

Where the tool is also to be employed in separating or lifting one part from the other, the socket in the driving .end of said plunger includes wrenching surfaces which fit correspondingly shaped non-circular surfaces of the terminal for application of twisting torque; and said driving end has an overhanging part or lifting flange for engagement with the terminal to pull it away from its engaged connector part.

Other objects and important features of the invention to which reference has not been made hereinabove will appear in the following description and claims.

Although in the accompanying drawings I have shown a preferred embodiment of my invention and have described the same and modifications thereof in this specification, it is to be understood that these are not intended to be either exhaustive or limiting of the invention, but on the contrary, are chosen for-the purposes of illustrating the invention in order that others skilled in the art may fully understand the invention, its principles and the application thereof, and that they may embody it and adapt it in numerous forms, each as may be best suited to the requirements of its particular use.

Figure l of the appended drawings i a side view on enlarged scale of a portion of the plunger of a tool embodying the present invention with one form of taper pin terminal and its lead wire shown in dotted lines engaged therewith and-with the free end of the plug in a position to be pressed into a suitable receptacle contact;

Figure -2 is a transverse section on the line 22 of Figure 1;

Figure 3 is a fragmentary side view with portions in axial section to illustrate more clearly the conformation of the terminal-engaging socket and wire slot;

Figure 4 is a central longitudinal sectional view of a plunger, hammerand spring assembly in a holder the end of said plunger corresponding'to that shown in Figure l being broken away;

Figure 5 isa transverse section on the line'S-e-S of .Figure. 4; and

as shown in Figure land hereinafter described. For more accurate control over the inserting force e. g for a taper pin connector, or receptacle, the terminal-engaging plunger of the tool may advantageously push against a spring-driven hammer to load its spring to, a predetermined extent, whereupon the hammer is released to be actuated .by the loaded spring and impact against another part of the plunger. 7

As shown in Figure 1, a tool according to the present invention includes a shank 1 which provides at its outer acting end or tool head a terminal-engaging socket 2.

The' end of said shank is divided by a'transverse slot 3 into opposed flanges 4'and 5 undercut by the outer end of socket 2 to'fo'rm inwardly directed shouiders 6.

The shank 1 also has a longitudinal groove 8 opening into the inner end of socket 2. These together form a continuous open'slot along one side of the shank.- Groove S is open along'a' side of the shank approximately 90 around its axis from the lateral opening of socket 2.

When used for connecting a taper pin terminal 9 into a receptacle contact, the terminal is positioned with its narrow neck portion 11 engaged in slot 3 between flanges .4 and 5 and with its wider insulation-engaging barrel 11 with the necessary force which may be applied by manual pressure on the tool handle, or by impact, or both.

The tool just described may also be employed as a puller or extractor for removing a terminal plug from a contact receptacle in which it is frictionally engaged. Where the parts resist separation by a simple pull, the

tool is applied with its slot 3 embracing neck of the plug as described above. The tool is then rotated about 7 its axis to loosen plug 9 which can then easily be pulled out by the tool shoulders 6 and 7 engaging the outer pcfree sliding fit in the lower portion of said bore, the lower end of the hammer having a central hole 22b.

Hammer 22 also has a transverse recess 27 (Fig. 6)

which receives a slidable detent 28 provided with a hole I 29 slidably fitted tothe upper shaft'of plunger 16. 'A

fiat spring 311, secured to one side of hammer 22 in r recess 31, is arranged with its free end extending into recess 27 and bearing against one side of detent 28 which is thus pushed against the opposite side of the bore. in holder as shown in Figures 4 and 6. The other end of detent 2 8 is rounded and extends radially beyond the opening of recess 27 to ride on the inner surface of the bore in holder 20.

' The inner end of plunger 16 extends through the hole 22b in hammer part 22a and may have an end'projection V 32 of reduced diameter extending beyond a shoulder- 33 ripheral shoulder portions 15 of barrel 11. Thus, plug 9 is removed without straining the wire 12 or its connection in plug 9.

Such a tool with rigidly connected handle and shank with socket according to this invention enables a careful skilled operator to make consistently perfect connections and to disconnect without damage; In ordinary manufacturing, however, less skilled and less careful operators must be employed for such work. A further improvement of my invention assures proper connection even with such operators. To this end the socket end portion above described and shown in Figure l is conveniently incorporated in or mounted on a plunger 16, Figure 4. The plunger shank 1 is keyed to the holder 20 (which forms the handle) e. g, by'having a lateral portion cut away to form a keyway and the resulting face engaging a fixed pin 19 which keys the shank 1 in the holder 20. Thus, plunger 16 is free to move'endwise but is prevented by pin 19 from rotating in holder 20 when the tool is used to loosen one connector from another by twisting as above described. 7

Holder 20 as shown is made in three sections threaded together and has a central longitudinal bore accommodating at its open end the plunger 16 pushed toward its ticular use.

socket end by a spring 21. A hammer 22 is slidably mounted inthe opposite closed end of said bore and is pushed toward the plunger 16 by a spring 23. A plug 24 screwed into the bore in the lower part of holder 20 serves as an abutment for spring 21 and has a central I opening 25 serving as arbearing to hold plunger 16 to its axial position during sliding movement.

The middle section of the holder 20 between said lower section and closed end section, has a bore which decreases in diameter toward the upper end so that an annular sloping cam-surface 26 is formed therein. The hammer22 is of diameter slightly less than the narrower portion of the bore so that it may slide freely therein.

annular flange 22:: at the lower end of said hammer has a which normally engages the detent 28 while said projection 32 extends into hole 29 of said detent.

'In operation, when pressure is applied to holder '20 in 'the direction of the arrow, Figure 1, and a wire'with' a terminal thereon is engaged in the socket, as seen in Figure 1, terminal 9 freely enters contact receptacle 14.:

When, with further inward movement of terminal 9, the frictional contact between said parts increases sufliciently, plunger 16 is moved inwardly compressing spring 21, the inner end of said plunger being pressed against detent 28 which moves hammer 22 upward against spring 23.

When this movement of hammer 22 brings the rounded end of detent 28 against shoulder 26, said detent is moved transversely against resistance of spring 31 until itshole 29 is'lined up with plunger 16 and thus it is dislodged from shoulder 33. The hammer when thus released, is

driven downward by spring 23 to deliver a sharp blow when the 'upper'end of plunger 16 strikes the inner end of the bore 35. in the hammer. The energy of thisimpact is predetermined by the characteristics of spring 23 and the depthof holes 29 and 35. The force exerted for initial seating of the terminal before the impact occurs is predetermined by the location of cam shoulder 26 and the characteristics of spring 23 (i. e., the loading of the spring at the point where the hammer is triggered for impact). When impact occurs, the operator knows that the inserting operation is complete. The mass of hammer 22 and the power factor to be supplied by springs21 and 23 will be designed for optimumdegree of insertion for a given type and size range of terminals and contacts to be, connected. This device is particularly advantageous with terminals and receptacles disclosed in the application Serial No. 400,996, filed December 29, 1953.

From the foregoing it is apparent that the terminal connecting tools described above are well suited to ,at-

tain the ends and objects herein directly and indirectly set forth; that they can be manufactured by conventional techniques; and that the various features and arrangements of parts can be modified readily so as best to suit apar- Certain features of the disclosure may be used to advantage in particular applications without a corresponding use. of other features, and the elimination V or modification of such features is to be construed as within the scope of this invention unless specifically excluded by the following claims or required by, the scope of the prior art.

I claim: a

l. A terminal applying tool comprising a shank havm 'at its head end, a'terminalreceiving longitudinal recess and an end wall defining the outer end of said recess, a

slot extending through said end wall coaxially and connecting, withsaid recess to form terminal engaging end flanges, and a wirereceiving groove opening through a lateral wall portion of said head and into an inner end portion of said recess, said groove being angularly ofiset fi'om said recess, said recess having a lateral opening extending between and connecting said slot and said groove.

2. .In a tool for connecting an electrical terminal and a contact where one of said parts provides a receptacle adapted to receive and frictionally engage a tapered plug portion of the other part, the combination of a holder provided with a longitudinal bore open at one end, a plunger slidably mounted and co-axial with said bore and spring biased to normally retain an outer end portion extending through and outwardly beyond said open end of the bore, a spring at the closed end of said bore, a hammer slidably mounted in said bore between the inner end of said plunger and said spring in the closed end of said bore, means interposed between said hammer and said plunger and normally spring biased toward a position to trans mit longitudinal inward movement of the plunger to said hammer and movable transversely of said bore to permit spring pressed outward movement of said hammer into direct striking engagement with said plunger at a predetermined position of inward movement of the plunger, said plunger having a head arranged and adapted to drivingly engage one of said connector parts, a longitudinally disposed recess, an end wall, a transverse slot extending through a portion of said end wall and into 0 said longitudinally disposed recess, said slot defining lateral edge portions of opposed terminal engaging flanges provided by said wall at the outer end of said longitudinal recess, and said recess having an opening through a lateral wall portion of the head co-axial and connected at its outer end with said end slot, and a wire receiving groove having a lateral opening angularly offset from and conmeeting with an inner end portion of said first mentioned lateral opening.

3. A tool according to claim 2 and wherein said slot is adapted to embrace a portion of said part which is of reduced cross section and said flanges are arranged and adapted to engage a portion of said part adjacent thereto and thereby lift said part from engagement with the other part, and means are operatively interposed between the plunger and the holder in position to retain said plunger against turning movement in relation to the holder.

References Cited in the file of this patent UNITED STATES PATENTS 651,267 Pickett June 5, 1900 848,211 Schnyder Mar. 26, 1907 1,111,380 Hanke Sept. 22, 1914 1,572,046 Seiler Feb. 9, 1926 2,673,393 Smith Mar. 30, 1954 

